US1531811A - Electric furnace - Google Patents

Description

March 31. 1925. 1,531,811

F. J. PETERSON ELECTRIC FURNACE Filed Dec. 26, 192;

gnovznfoz mlr'son w am attoznaq Patented i925.

hula Sit FEEDOLF J. PETERSON, 0F DETROIT, MICHIGAN.

ELECT'RZG FURHAQE.

Application filed December 26, W23. Serial Ito. 682,664.

and useful improvements in Electrical Furnaces, of which the following is a specification.

This invention relates to an electric furnace especially adapted to use in melting metal.

In the prior art there are some patents which show rotating electric furnaces and other furnaces which are given a rocking motion. the purpose of which is to mechanically mix the molten metal so that the different elements that go to make up the alloy metal will be mixed. Also. there are furnaces which are given a reciprocating movement. which aim to so shake the molten mass that the same will he mixed. However. with a circular furnace which rotates or rocks. the molten metal merely slides up and down the curved sides of the furnace. and in the reciprocating furnace the metal is merely shaken and not thoroughly mixed. It has been the custom in the past to use the rotating or roclo' ing circular furnaces as these seem to provide a better mix. However. with some alloying metals that are used. as for instance,lead. it is found that the rotating or rocking circular furnace will not thoroughly mix this alloying metal with the other metal. aresometimes likened to oil and water. as the lead is so much heavier than the other metal that it sinks to the bottom and does not become mixed with the metal near the surface in a satisfactory manner.

The object of the present invention is to so construct a furnace that when a movement is imparted to the furnace to move the same back and forth. the metal will be caused to describe a path similar to a figure 8. the metal thereby being overturned and thoroughly mined as a result of this overturning action. The metal near the bottom of the container is forced up the curved side walls of the furnace and is slopped over onto the molten mass thereby causing the alloying metal to pass through the base metal and become thoroughly mixed therewith. Another advantage is that the heat for melting the metal is generally projected Lead and other metalsdown on the surface of the metal from. above. thereby causing the molten mass near the surface to have a higher temperature than the metal near the bottom of the container chamber. 'With my principle of mixing, the colder metal from near the bottom is overturned onto the hotter metal near the top, and therefore. a more even heat obtained throughout the entire .mass.

In the drawings: 7

Fig. 1 is a longitudinal section through the electric furnace showing my improved construction.

Fig. 2 is a vertical section taken on the line 22 of Fig. 1.

The furnace comprises an outer shell a, preferably of steel and adjacent this outer shell is a layer of insulating material 5. The furnace is constructed with a comcomposite lining comprising a layer of fire brick c, and a lining of refractory material. known as carborundum, designated 01. This interior lining of the furnace is adapted for use in melting metal alloys as the characteristics of the said lining are such that the alloying metal will not readily adhere to the lining, and all the alloying metal is thoroughly and mechanically mixed with the base metal for forming the metal alloy. The container chamber e of the furnace is constructed substantially oval in cross section. as shown in Fig. 1, the major axis of which is greater than. the minor axis. However. the bottom of the furnace is preferably flattcndcd as at f; the ends are curved. sharply upward for a purpose that will hereinafter be explained. Electrodes 9 supported by the furnace extend into the interior of the container chamber and when the current is turned on, the electric arc provides the heat for melting the metal ingots which have been placed in the container chamber.

The furnace is bolted or otherwise se cured to a base plate 71, which rotatably supports in suitable bearings, the rollers or wheels '5 guided on the'tracks 7'', carried by the frame 70 which is pivotally supported as at m to the supporting frame 42. A motor M is carried by the frame k, the said motor directly driving the disc or crank 0 to which is connected the link or crank arm p. As shown in Fig. 1., it will be no= ticed that as the motor M is operated, the crank o, and crank arm p which is connected to the furnace as at will reciprocate the furnace back and forth, the furnace guided in said reciprocating movement by the Wheels or rollers c' riding on the tracks This reciprocating movement is relatively rapid and the metal which is now molten due to the excessive heat within the furnace is caused to slop back and forth Within the container.

1 have shown, by means of arrows in Fig. 1, substantially the path described by the molten metal as the furnace is reciprocated back and forth. The molten metal will be forced up the curved ends of the container chamber and overturned inwardly towards the center of the furnace and describes a path which is substantially a figure 8. This movement of the molten mass causes the metal near the bottom of the container chamber to be overturned onto the surface of the molten mass, thereby causing the metal to pass through and all parts of the. mass become thoroughly mixed. The excessiveheat generated by the electric arc is directed onto the surface of the molten mass and as a result the liquid near the surface is hotter than that adjacent the bottom of the container. My method of agitating the furnace causes the colder metal near the bottom to overturn onto the hotter liquid near the surface. This causes the colder liquid to mix with the hotter liquid and results in a more uniform temperature throughout the entire molten mass. When using lead as an alloying metal, or metal possessing similar characteristics, it has been found that the melted lead will sink to the bottom as it is heavier than therest of the molten metal used as a base. lVith my principle of agitating the furnace, this alloying metal near the bottom of the container chamber is caused to be overturned as described, thereby passing the alloying metal directly through the entire molten mass. Oloviously, a better mix is obtained and the alloying metal evenly and thoroughly mixed with the base metal.

The container chamber being flattened along the bottom enables the molten metal to be given a push along the horizontal plane so that when the molten metal reaches the curved ends, it is forced up and due to the sharpness of the curves, it is forced inwardly in an arc and falls on the surface of the. molten mass, thereby obtaining a mix that is practically 100% .eficient. Some base metals of course, which possess a specific gravity near the specific gravity of the alloying metal are readil mixedb a rotating furnace, but quite 0 en the a loying metal possesses a greater specific gravity and consequently it is not readily mixed by a rotating furnace. My principle of mixing which causes the alloying metal to pass through the entire molten mass, enables one to use any kind of alloying metal, no matter what the specific gravity, and thoroughly mix the entire molten mass.

Another advantage in using a furnace of this design is that the reciprocating mov ment may be started before the ingots ar entirely melted, the liquid resulting from the partial melting of the ingots 15 thus caused to slop over the solid mass and results in melting the ingots more quickly. In addition, the back-and-forth movement of the furnace causes the solids to slide back and forth along the bottom, and tends to keep the bottom of the container chamber clean, and prevents the formation of a crust along the interior bottom wall of the container chamber. One diificulty with the rotating furnace is that the alloying metal of greater specific gravity than the base metal and which tends to stay near the bottom of the container, more readily adheres to the lining than the base metal to which it is to be united. With my method of overturning the metal the alloying metal is constantly being lifted and thrown onto the surface of the molten mass, and tends to keep the alloying metal away from the bottom ot the container chamber, and thus there is less likelihood of the alloying metal adhering to the bottom furnace lining.

The usual filler opening and pouring spout s are provided in the furnace. The worm gear t carried by the pivot shaft m meshes with the worm a which can be hand operated for the purpose of tilting the frame is, which slidably supports the furnace proper. When it 'is desired to emptythe furnace, the above mentioned mechanism may be actuated to tilt the furnace so as to pour the molten mass out through the outlet port or pouring spout a.

The same movement of the molten mass within the container chamber may be obtained by rocking the furnace instead of imparting a reciprocating movement to the same. In my claims I have used the term mov ng the furnace back and forth in its broadest significance to cover either a reciprocating movement or a rocking movement of, the furnace. Either movement will cause the molten mass within the container chamber to move back and forth, that is, to cause the mass to attain a sufiicient velocity thereby causing the same to be forced up the curved end walls and to be slopped over onto the surface of the molten metal as described.

What it claim is:

1. A movable electric furnace, having a container chamber for holding a liquid, and means for moving the said furnace back and forth, the container arranged to turn the liquid over at both ends and cause the liquid to describe a path substantially a figill are S, -for the purpose of mechanically mixing the liquid,

2, it movable electric furnace having a container chamber for holding a liquid,

said chamber substantially elliptical in cross section, and. means for 'moving sairl furnace back anti forth, the container arrangeol to turn the liquid; over and cause the liquid to describe a: path substantially a figure 8 for the purpose of mechanically mixing the liquid,

3. A movable electric furnace having a container chamber for holding a liquid, said chamber pK'GVld'E3llWll-h curvecl curl Walls merging into a flattened bottom Wall amt substantially elliptical in cross section, and means for moving said furnace. heel: and forth whereby the curved entl Walls turn the liquid over at both encls and cause the liquicl to describe a path substantially a figure 8, for the purpose @ll mechanically mixing the liquitl.

4. A movable electr1c ,turnace having a container chamber for holclin a liquid, saiol chamber being substantially elliptical in cross section and having curved enrl walls and the bottom fiattenedintermetliate the said curved entls and merged therewith, and means for moving said furnace back and forth whereby the curved end walls overturn the liquid at both ends'ot the furnace and cause the liquiol to describe a path substantially a figure 3, for the purpose of mechanically mining the liquid.

5. A movable electric furnace having a container chamber for holcling a liquid, means for heating the liquicl -t'roin above thereby causing the liquid-near the surface to have a higher temperature than the liquid adjacent the bottom of the container, said container chamber being substantially elliptical in cross section and. provided, with curverl ends and a flattened bottom merged thereinto, and means for moving said lurnace back and forth whereby the curved ends overturn the liquid at both entls oil the fun mace and cause the liquiol to describe a path substantially of a figure 8, for the purpose of overturning the colder liquicl onto the "sharplycurvedl and the bottom port-ion flattenecl, the curved ends both merging into the flattened bottom portion, and means for moving said turnace back and forth whereby the sharply curved curls cause the metal to overturn at both ends and to describe a figure 8 for thepurpose of mechanically mire ing the liquid.

7., A movable electric furnace havhig container chamber for holding a liquid, anti means for reciprocating Snltl furnace back and forth, the container constructed to overturn the liq'uiol at both ends and cause the liquid to describe a path substantially a figure ti tor the purpose of mechanically mixing the same.

8. A movable electric furnace having a container chamber for holding a liquicl, said chamber being substantially elliptical in cross section ancl having curved and Walls anol a flattened bottom, the curvccl entls merging into the bottom portion and means for reciprocating said furnace back and forth, whereby the liquirl is caused to clescribe a path substantially. a figure for the purpose of mechanically mixing the same, i I

9. A movable electric furnace, having container chamber for holding a liquid, track torsupporting saicl furnace, means for reciprocating saicl furnace baclr anti forth, the same being guiclecl in such move ment on saicl track, the container arrangetl to alternately turn over the liquicl at both ends and causethe liquid to describe a path substantially out a figure 5%, for the purpose of mechanically mixing the same, and means for retaining the furnace on saiol track to preventthe same from tilting or jumping the track while being reciprocateu In testimony whereof l have afixecl my signature. V

FREDOLF J. PETERSQN Til

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